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Alva R, Wiebe JE, Stuart JA. The effect of baseline O 2 conditions on the response of prostate cancer cells to hypoxia. Am J Physiol Cell Physiol 2024; 327:C97-C112. [PMID: 38646786 DOI: 10.1152/ajpcell.00155.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/14/2024] [Accepted: 04/15/2024] [Indexed: 04/23/2024]
Abstract
The transcriptional response to hypoxia is largely regulated by the hypoxia-inducible factors (HIFs), which induce the expression of genes involved in glycolysis, angiogenesis, proliferation, and migration. Virtually all cell culture-based hypoxia experiments have used near-atmospheric (18% O2) oxygen levels as the baseline for comparison with hypoxia. However, this is hyperoxic compared with mammalian tissue microenvironments, where oxygen levels range from 2% to 9% O2 (physioxia). Thus, these experiments actually compare hyperoxia to hypoxia. To determine how the baseline O2 level affects the subsequent response to hypoxia, we cultured PC-3 prostate cancer cells in either 18% or 5% O2 for 2 wk before exposing them to hypoxia (∼1.1% pericellular O2) for 12-48 h. RNA-seq revealed that the transcriptional response to hypoxia was dependent on the baseline O2 level. Cells grown in 18% O2 before hypoxia exposure showed an enhanced induction of HIF targets, particularly genes involved in glucose metabolism, compared with cells grown in physioxia before hypoxia. Consistent with this, hypoxia significantly increased glucose consumption and metabolic activity only in cells previously cultured in 18% O2, but not in cells preadapted to 5% O2. Transcriptomic analyses also indicated effects on cell proliferation and motility, which were followed up by functional assays. Although unaffected by hypoxia, both proliferation and migration rates were greater in cells cultured in 5% O2 versus 18% O2. We conclude that an inappropriately hyperoxic starting condition affects the transcriptional and metabolic responses of PC-3 cells to hypoxia, which may compromise experiments on cancer metabolism in vitro.NEW & NOTEWORTHY Although human cell culture models have been instrumental to our understanding of the mechanisms involved in the cellular response to hypoxia, in virtually all experiments, cells are routinely cultured in near-atmospheric (∼18% O2) oxygen levels, which are hyperoxic relative to physiological conditions in vivo. Here, we show for the first time that cells cultured in physiological O2 levels (5% O2) respond differently to subsequent hypoxia than cells grown at 18%.
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Affiliation(s)
- Ricardo Alva
- Department of Biological SciencesBrock University, St. Catharines, Ontario, Canada
| | - Jacob E Wiebe
- Department of Biological SciencesBrock University, St. Catharines, Ontario, Canada
| | - Jeffrey A Stuart
- Department of Biological SciencesBrock University, St. Catharines, Ontario, Canada
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2
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Rogers ZJ, Colombani T, Khan S, Bhatt K, Nukovic A, Zhou G, Woolston BM, Taylor CT, Gilkes DM, Slavov N, Bencherif SA. Controlling Pericellular Oxygen Tension in Cell Culture Reveals Distinct Breast Cancer Responses to Low Oxygen Tensions. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2402557. [PMID: 38874400 DOI: 10.1002/advs.202402557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/11/2024] [Indexed: 06/15/2024]
Abstract
In oxygen (O2)-controlled cell culture, an indispensable tool in biological research, it is presumed that the incubator setpoint equals the O2 tension experienced by cells (i.e., pericellular O2). However, it is discovered that physioxic (5% O2) and hypoxic (1% O2) setpoints regularly induce anoxic (0% O2) pericellular tensions in both adherent and suspension cell cultures. Electron transport chain inhibition ablates this effect, indicating that cellular O2 consumption is the driving factor. RNA-seq analysis revealed that primary human hepatocytes cultured in physioxia experience ischemia-reperfusion injury due to cellular O2 consumption. A reaction-diffusion model is developed to predict pericellular O2 tension a priori, demonstrating that the effect of cellular O2 consumption has the greatest impact in smaller volume culture vessels. By controlling pericellular O2 tension in cell culture, it is found that hypoxia vs. anoxia induce distinct breast cancer transcriptomic and translational responses, including modulation of the hypoxia-inducible factor (HIF) pathway and metabolic reprogramming. Collectively, these findings indicate that breast cancer cells respond non-monotonically to low O2, suggesting that anoxic cell culture is not suitable for modeling hypoxia. Furthermore, it is shown that controlling atmospheric O2 tension in cell culture incubators is insufficient to regulate O2 in cell culture, thus introducing the concept of pericellular O2-controlled cell culture.
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Affiliation(s)
- Zachary J Rogers
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Thibault Colombani
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Saad Khan
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
| | - Khushbu Bhatt
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA
| | - Alexandra Nukovic
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Guanyu Zhou
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Benjamin M Woolston
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
| | - Cormac T Taylor
- Conway Institute of Biomolecular and Biomedical Research and School of Medicine, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland
| | - Daniele M Gilkes
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, 21321, USA
- Cellular and Molecular Medicine Program, The Johns Hopkins University School of Medicine, Baltimore, MD, 21321, USA
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD, 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Nikolai Slavov
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
- Departments of Bioengineering, Biology, Chemistry and Chemical Biology, Single Cell Center and Barnett Institute, Northeastern University, Boston, MA, 02115, USA
- Parallel Squared Technology Institute, Watertown, MA, 02472, USA
| | - Sidi A Bencherif
- Department of Chemical Engineering, Northeastern University, Boston, MA, 02115, USA
- Department of Bioengineering, Northeastern University, Boston, MA, 02115, USA
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
- Biomechanics and Bioengineering (BMBI), UTC CNRS UMR 7338, University of Technology of Compiègne, Sorbonne University, Compiègne, 60203, France
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Montserrat-Mesquida M, Ferrer MD, Pons A, Sureda A, Capó X. Effects of chronic hydrogen peroxide exposure on mitochondrial oxidative stress genes, ROS production and lipid peroxidation in HL60 cells. Mitochondrion 2024; 76:101869. [PMID: 38467292 DOI: 10.1016/j.mito.2024.101869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 02/25/2024] [Accepted: 03/07/2024] [Indexed: 03/13/2024]
Abstract
Hydrogen peroxide (H2O2) is a reactive species that is also involved in the redox regulation of cells because of it is relative stability. In numerous pathological situations, a chronic increase in the production of reactive species is observed, which is related to oxidative stress and cellular damage. This study aimed to evaluate the effects of long-term exposure to different H2O2 concentrations on oxidative stress biomarkers and mitochondrial dynamics in HL60 cells. HL60 cells were treated with a sustained production (0.1, 1.0 and 10.0 nM/s) of H2O2 for one hour. H2O2 production and malondialdehyde (MDA) levels, as a lipid peroxidation marker, increased progressively in HL60 cells in accordance with higher H2O2 exposure, with significant differences between the 10 nM/s H2O2 group and the control and 0.1 nM/s groups. Similarly, progressive increased expression in genes related to the mitochondrial antioxidant defences and mitochondrial dynamics were also observed. Significantly increased gene expression in the 10 nM/s H2O2 with respect to the control group was observed for manganese superoxide dismutase (MnSOD), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PCG1α), nuclear respiratory factor 2 (Nrf2), mitochondrial transcription factor A (Tfam), mitofusins 1 and 2 (Mfn1 and Mfn2) and uncoupling protein 3 (UCP3), whereas no significant changes were observed in the cytochrome c oxidase subunit IV (COXIV) gene expression. In conclusion, exposure to different sustained production of H2O2 is related to a progressive increase in the gene expression of mitochondrial dynamics and redox processes in HL60 cells, but also to oxidative damage at higher H2O2 production levels.
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Affiliation(s)
- M Montserrat-Mesquida
- Research Group in Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS, 07122 Palma, Spain; Health Research Institute of Balearic Islands (IdISBa), 07120 Palma, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
| | - M D Ferrer
- Research Group in Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS, 07122 Palma, Spain
| | - A Pons
- Research Group in Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS, 07122 Palma, Spain; Health Research Institute of Balearic Islands (IdISBa), 07120 Palma, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
| | - A Sureda
- Research Group in Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS, 07122 Palma, Spain; Health Research Institute of Balearic Islands (IdISBa), 07120 Palma, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain.
| | - X Capó
- Research Group in Community Nutrition and Oxidative Stress, University of the Balearic Islands-IUNICS, 07122 Palma, Spain; Translational Research in Aging and Longevity (TRIAL) Group, Health Research Institute of the Balearic Islands (IdISBa), 07120 Palma, Spain
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Jurčacková Z, Ciglanová D, Mudroňová D, Bárcenas-Pérez D, Cheel J, Hrčková G. Influence of standard culture conditions and effect of oleoresin from the microalga Haematococcus pluvialis on splenic cells from healthy Balb/c mice - a pilot study. In Vitro Cell Dev Biol Anim 2023; 59:764-777. [PMID: 38062299 PMCID: PMC10739404 DOI: 10.1007/s11626-023-00822-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/17/2023] [Indexed: 12/22/2023]
Abstract
In this work, we used splenocytes from healthy mice to study the effects of the two most commonly used cell culture media (A, B) with different compositions of redox reagents. The incubation of cells for 24 h resulted in a significant decrease in viability and metabolic activity of splenocytes, and the negative effects of incubation in medium B were more pronounced. In standard conditions, oxidative stress in cells was manifested by reduced mitochondrial potential, and this effect correlated with the transition of 58.3% of cells to the early stage of apoptosis under reducing conditions of medium A and up to 66.1% of cells under super-reducing conditions in medium B, suggesting altered cell physiology. High levels of ROS/RNS activated transcription factor Nrf2, superoxide dismutase 1, and catalase. The higher mRNA levels of these genes were under the conditions of medium B, whose super-reducing environment in combination with the environment of conventional incubators proved to be less suitable for the cells compared to medium A. Treatment of the cells with a lower concentration (10 µg/ml) of oleoresin obtained from the microalga H. pluvialis partially eliminated the negative effects of cultivation. Higher concentration of oleoresin (40 µg/ml) was slightly cytotoxic, due to the significant antioxidant effect of astaxanthin, the main bioactive component of the extract, which eliminated most of the ROS/RNS acting as signalling molecules. This study shows that the standard culture conditions do not reflect the physiological in vivo cell conditions; therefore, they are not generally suitable for incubation of all cell types.
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Affiliation(s)
- Zuzana Jurčacková
- Institute of Parasitology, The Slovak Academy of Sciences, Hlinkova 3, 04001, Košice, Slovakia
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenského 68, 04181, Košice, Slovakia
| | - Denisa Ciglanová
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenského 68, 04181, Košice, Slovakia
| | - Dagmar Mudroňová
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenského 68, 04181, Košice, Slovakia
| | - Daniela Bárcenas-Pérez
- Laboratory of Algal Biotechnology - Centre ALGATECH, Institute of Microbiology of the Czech Academy of Sciences, Opatovický Mlýn, 37981, Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská, 1760, 37005, České Budějovice, Czech Republic
| | - José Cheel
- Laboratory of Algal Biotechnology - Centre ALGATECH, Institute of Microbiology of the Czech Academy of Sciences, Opatovický Mlýn, 37981, Třeboň, Czech Republic.
| | - Gabriela Hrčková
- Institute of Parasitology, The Slovak Academy of Sciences, Hlinkova 3, 04001, Košice, Slovakia.
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Rogers ZJ, Colombani T, Khan S, Bhatt K, Nukovic A, Zhou G, Woolston BM, Taylor CT, Gilkes DM, Slavov N, Bencherif SA. Controlling pericellular oxygen tension in cell culture reveals distinct breast cancer responses to low oxygen tensions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560369. [PMID: 37873449 PMCID: PMC10592900 DOI: 10.1101/2023.10.02.560369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Oxygen (O2) tension plays a key role in tissue function and pathophysiology. O2-controlled cell culture, in which the O2 concentration in an incubator's gas phase is controlled, is an indispensable tool to study the role of O2 in vivo. For this technique, it is presumed that the incubator setpoint is equal to the O2 tension that cells experience (i.e., pericellular O2). We discovered that physioxic (5% O2) and hypoxic (1% O2) setpoints regularly induce anoxic (0.0% O2) pericellular tensions in both adherent and suspension cell cultures. Electron transport chain inhibition ablates this effect, indicating that cellular O2 consumption is the driving factor. RNA-seq revealed that primary human hepatocytes cultured in physioxia experience ischemia-reperfusion injury due to anoxic exposure followed by rapid reoxygenation. To better understand the relationship between incubator gas phase and pericellular O2 tensions, we developed a reaction-diffusion model that predicts pericellular O2 tension a priori. This model revealed that the effect of cellular O2 consumption is greatest in smaller volume culture vessels (e.g., 96-well plate). By controlling pericellular O2 tension in cell culture, we discovered that MCF7 cells have stronger glycolytic and glutamine metabolism responses in anoxia vs. hypoxia. MCF7 also expressed higher levels of HIF2A, CD73, NDUFA4L2, etc. and lower levels of HIF1A, CA9, VEGFA, etc. in response to hypoxia vs. anoxia. Proteomics revealed that 4T1 cells had an upregulated epithelial-to-mesenchymal transition (EMT) response and downregulated reactive oxygen species (ROS) management, glycolysis, and fatty acid metabolism pathways in hypoxia vs. anoxia. Collectively, these results reveal that breast cancer cells respond non-monotonically to low O2, suggesting that anoxic cell culture is not suitable to model hypoxia. We demonstrate that controlling atmospheric O2 tension in cell culture incubators is insufficient to control O2 in cell culture and introduce the concept of pericellular O2-controlled cell culture.
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Affiliation(s)
- Zachary J. Rogers
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
| | - Thibault Colombani
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
| | - Saad Khan
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
| | - Khushbu Bhatt
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Alexandra Nukovic
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
| | - Guanyu Zhou
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
| | - Benjamin M. Woolston
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
| | - Cormac T. Taylor
- Conway Institute of Biomolecular and Biomedical Research and School of Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Daniele M. Gilkes
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21321, USA
- Cellular and Molecular Medicine Program, The Johns Hopkins University School of Medicine, Baltimore, MD 21321, USA
- Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
- Johns Hopkins Institute for NanoBioTechnology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Nikolai Slavov
- Departments of Bioengineering, Biology, Chemistry and Chemical Biology, Single Cell Center and Barnett Institute, Northeastern University, Boston, MA 02115 USA
- Parallel Squared Technology Institute, Watertown, MA 02135 USA
| | - Sidi A. Bencherif
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Biomechanics and Bioengineering (BMBI), UTC CNRS UMR 7338, University of Technology of Compiègne, Sorbonne University, 60203 Compiègne, France
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Jurčacková Z, Ciglanová D, Mudroňová D, Tumová L, Bárcenas-Pérez D, Kopecký J, Koščová J, Cheel J, Hrčková G. Astaxanthin Extract from Haematococcus pluvialis and Its Fractions of Astaxanthin Mono- and Diesters Obtained by CCC Show Differential Antioxidant and Cytoprotective Effects on Naïve-Mouse Spleen Cells. Antioxidants (Basel) 2023; 12:1144. [PMID: 37371874 DOI: 10.3390/antiox12061144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Carotenoids are the most abundant lipid-soluble phytochemicals and are used as dietary supplements to protect against diseases caused by oxidative stress. Astaxanthin, a xanthophyll carotenoid, is a very potent antioxidant with numerous beneficial effects on cellular functions and signaling pathways. In this study, using spleen cells from healthy Balb/c mice, we report the bio-functional effects of an astaxanthin-rich extract (EXT) prepared from the microalga Haematococcus pluvialis and its astaxanthin monoesters-rich fraction (ME) and astaxanthin diesters-rich fraction (DE) obtained by fractionation of EXT using countercurrent chromatography (CCC). After incubation under standard culture conditions (humidity, 37 °C, 5% CO2, atmospheric oxygen), the viability of untreated splenocytes, as determined by the trypan blue exclusion assay, the MTT assay, and the neutral red assay, decreases to approximately 75% after 24 h compared with naïve splenocytes. This effect correlated with the decrease in mitochondrial membrane potential and the transition of ~59% of cells to the early stage of apoptosis, as well as with the decreased ROS production, indicating that hyperoxia in cell-culture deteriorates cell functions. They are restored or stimulated by co-cultivation with EXT, ME, and DE up to 10 µg/mL in the order EXT > DE > ME, suggesting that esterification increases bioavailability to cells in vitro. ROS and H2O2 concentrations reflect mRNA transcriptional activity of Nrf2, superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 1, as well as SOD-mediated ROS conversion, whereas they inversely correlate with iNOS-mediated NO production. The highest-tested concentration of EXT, ME, and DE (40 µg/mL) is detrimental to cells, probably because of the overwhelming scavenging activity of astaxanthin and its esters for the reactive oxygen/nitrogen species required for cellular functions and signal transduction at low physiological concentrations. In this study, we demonstrate that differential activities of ME and DE contribute to the final antioxidant and cytoprotective effects of astaxanthin extract, which is beneficial in preventing a wide range of ROS-induced adverse effects, with DE being more effective. In addition, the selection of physioxia-like conditions for pharmacological research is highlighted.
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Affiliation(s)
- Zuzana Jurčacková
- Institute of Parasitology, The Slovak Academy of Sciences, Hlinkova 3, 04001 Košice, Slovakia
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenského 68, 04181 Košice, Slovakia
| | - Denisa Ciglanová
- Institute of Parasitology, The Slovak Academy of Sciences, Hlinkova 3, 04001 Košice, Slovakia
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenského 68, 04181 Košice, Slovakia
| | - Dagmar Mudroňová
- Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenského 68, 04181 Košice, Slovakia
| | - Lenka Tumová
- Department of Pharmacognosy and Botany, Faculty of Pharmacy Hradec Králové, Charles University, Heyrovského 1203, 50165 Hradec Králové, Czech Republic
| | - Daniela Bárcenas-Pérez
- Laboratory of Algal Biotechnology-Centre ALGATECH, Institute of Microbiology of the Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Jiří Kopecký
- Laboratory of Algal Biotechnology-Centre ALGATECH, Institute of Microbiology of the Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
| | - Jana Koščová
- Laboratory of Algal Biotechnology-Centre ALGATECH, Institute of Microbiology of the Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
| | - José Cheel
- Laboratory of Algal Biotechnology-Centre ALGATECH, Institute of Microbiology of the Czech Academy of Sciences, Opatovický mlýn, 37981 Třeboň, Czech Republic
| | - Gabriela Hrčková
- Institute of Parasitology, The Slovak Academy of Sciences, Hlinkova 3, 04001 Košice, Slovakia
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Abstract
Lytic polysaccharide monooxygenases (LPMOs) are unique redox enzymes capable of disrupting the crystalline surfaces of industry-relevant recalcitrant polysaccharides, such as chitin and cellulose. Historically, LPMOs were thought to be slow enzymes relying on O2 as the co-substrate, but it is now clear that these enzymes prefer H2O2, allowing for fast depolymerization of polysaccharides through a peroxygenase reaction. Thus, quantifying H2O2 in LPMO reaction set-ups is of a great interest. The horseradish peroxidase (HRP)/Amplex Red (AR) assay is one of the most popular and accessible tools for measuring hydrogen peroxide. This assay has been used in various types of biological and biochemical studies, including LPMO research, but suffers from pitfalls that need to be accounted for. In this Chapter, we discuss this method and its use for assessing the often rate-limiting in situ formation of H2O2 in LPMO reactions. We show that, after accounting for multiple potential side reactions, quantitative data on H2O2 production obtained with the HRP/Amplex Red assay provide useful clues for understanding the catalytic activity of LPMOs, including the impact of reductants and transition metal ions.
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Affiliation(s)
- Anton A Stepnov
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, Ås, Norway.
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Alva R, Moradi F, Liang P, Stuart JA. Culture of Cancer Cells at Physiological Oxygen Levels Affects Gene Expression in a Cell-Type Specific Manner. Biomolecules 2022; 12:1684. [PMID: 36421698 PMCID: PMC9688152 DOI: 10.3390/biom12111684] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 02/26/2024] Open
Abstract
Standard cell culture is routinely performed at supraphysiological oxygen levels (~18% O2). Conversely, O2 levels in most mammalian tissues range from 1-6% (physioxia). Such hyperoxic conditions in cell culture can alter reactive oxygen species (ROS) production, metabolism, mitochondrial networks, and response to drugs and hormones. The aim of this study was to investigate the transcriptional response to different O2 levels and determine whether it is similar across cell lines, or cell line-specific. Using RNA-seq, we performed differential gene expression and functional enrichment analyses in four human cancer cell lines, LNCaP, Huh-7, PC-3, and SH-SY5Y cultured at either 5% or 18% O2 for 14 days. We found that O2 levels affected transcript abundance of thousands of genes, with the affected genes having little overlap between cell lines. Functional enrichment analysis also revealed different processes and pathways being affected by O2 in each cell line. Interestingly, most of the top differentially expressed genes are involved in cancer biology, which highlights the importance of O2 levels in cancer cell research. Further, we observed several hypoxia-inducible factor (HIF) targets, HIF-2α targets particularly, upregulated at 5% O2, consistent with a role for HIFs in physioxia. O2 levels also differentially induced the transcription of mitochondria-encoded genes in most cell lines. Finally, by comparing our transcriptomic data from LNCaP and PC-3 with datasets from the Prostate Cancer Transcriptome Atlas, a correlation between genes upregulated at 5% O2 in LNCaP cells and the in vivo prostate cancer transcriptome was found. We conclude that the transcriptional response to O2 over the range from 5-18% is robust and highly cell-type specific. This latter finding indicates that the effects of O2 levels are difficult to predict and thus highlights the importance of regulating O2 in cell culture.
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Affiliation(s)
- Ricardo Alva
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Fereshteh Moradi
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
- Centre for Biotechnology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Jeffrey A. Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
- Centre for Biotechnology, Brock University, St. Catharines, ON L2S 3A1, Canada
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9
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Alva R, Mirza M, Baiton A, Lazuran L, Samokysh L, Bobinski A, Cowan C, Jaimon A, Obioru D, Al Makhoul T, Stuart JA. Oxygen toxicity: cellular mechanisms in normobaric hyperoxia. Cell Biol Toxicol 2022; 39:111-143. [PMID: 36112262 PMCID: PMC9483325 DOI: 10.1007/s10565-022-09773-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/07/2022] [Indexed: 12/15/2022]
Abstract
In clinical settings, oxygen therapy is administered to preterm neonates and to adults with acute and chronic conditions such as COVID-19, pulmonary fibrosis, sepsis, cardiac arrest, carbon monoxide poisoning, and acute heart failure. In non-clinical settings, divers and astronauts may also receive supplemental oxygen. In addition, under current standard cell culture practices, cells are maintained in atmospheric oxygen, which is several times higher than what most cells experience in vivo. In all the above scenarios, the elevated oxygen levels (hyperoxia) can lead to increased production of reactive oxygen species from mitochondria, NADPH oxidases, and other sources. This can cause cell dysfunction or death. Acute hyperoxia injury impairs various cellular functions, manifesting ultimately as physiological deficits. Chronic hyperoxia, particularly in the neonate, can disrupt development, leading to permanent deficiencies. In this review, we discuss the cellular activities and pathways affected by hyperoxia, as well as strategies that have been developed to ameliorate injury.
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Affiliation(s)
- Ricardo Alva
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Maha Mirza
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Adam Baiton
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Lucas Lazuran
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Lyuda Samokysh
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Ava Bobinski
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Cale Cowan
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Alvin Jaimon
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Dede Obioru
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Tala Al Makhoul
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Jeffrey A Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada.
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10
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Gardner G, Moradi F, Moffatt C, Cliche M, Garlisi B, Gratton J, Mehmood F, Stuart JA. Rapid nutrient depletion to below the physiological range by cancer cells cultured in Plasmax. Am J Physiol Cell Physiol 2022; 323:C823-C834. [DOI: 10.1152/ajpcell.00403.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mammalian cell culture is a fundamental tool used to study living cells. Presently, the standard protocol for performing cell culture involves the use of commercial media that contain an excess of nutrients. While this reduces the likelihood of cell starvation, it creates non-physiologic culture conditions that have been shown to 're-wire' cellular metabolism. Recently, researchers have developed new media like Plasmax, formulated to approximate the nutrient composition of human blood plasma. Although this represents an improvement in cell culture practice, physiologic media may be vulnerable to nutrient depletion. In this study we directly addressed this concern by measuring the rates of glucose and amino acid depletion from Plasmax in several cancer cell lines (PC-3, LNCaP, MCF-7, SH-SY5Y) over 48 hours. In all cell lines, depletion of glucose from Plasmax was rapid such that, by 48h, cells were hypoglycemic (<2mM glucose). Most amino acids were similarly rapidly depleted to sub-physiological levels by 48h. In contrast, glucose and most amino acids remained within the physiological range at 24h. When the experiment was done at physiological oxygen (5%) versus standard (18%) with LNCaP cells, no effect on glucose or amino acid consumption was observed. Using RNA sequencing, we show that this nutrient depletion is associated with enrichment of starvation responses, apoptotic signalling, and endoplasmic reticulum stress. A shift from glycolytic metabolism to mitochondrial respiration at 5% O2 was also measured using Seahorse analysis. Taken together, these results exemplify the metabolic considerations for Plasmax, highlighting that cell culture in Plasmax requires daily media exchange.
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Affiliation(s)
- Georgina Gardner
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Feresteh Moradi
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Christopher Moffatt
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Meagan Cliche
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Bianca Garlisi
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - John Gratton
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Fatima Mehmood
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Jeffrey A. Stuart
- Department of Biological Sciences, Brock University, St Catharines, Ontario, Canada
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11
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Siao YJ, Peng CC, Tung YC, Chen YF. Comparison of Hydrogen Peroxide Secretion From Living Cells Cultured in Different Formats Using Hydrogel-Based LSPR Substrates. Front Bioeng Biotechnol 2022; 10:869184. [PMID: 35464720 PMCID: PMC9031350 DOI: 10.3389/fbioe.2022.869184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 03/22/2022] [Indexed: 12/04/2022] Open
Abstract
Reactive oxygen species (ROS), a number of reactive molecules and free radicals derived from molecular oxygen, are generated as by-products during mitochondrial electron transport within cells. Physiologically, cells are capable of metabolizing the ROS exploiting specific mechanisms. However, if excessive ROS accumulate inside the cells, it will cause the cells apoptosis or necrosis. Hydrogen peroxide (H2O2) is one of the essential ROS often participating in chemical reactions in organisms and regulating homeostasis in the body. Therefore, rapid and sensitive detection of H2O2 is a significant task in cell biology research. Furthermore, it has been found that cells cultured in different formats can result in different cellular responses and biological activities. In order to investigate the H2O2 secretion from the cells cultured in different formats, a hydrogel-based substrate is exploited to separate relatively large molecular (e.g., proteins) for direct measurement of H2O2 secreted from living cells in complete cell culture medium containing serum. The substrate takes advantage of the localized surface plasmon resonance (LSPR) method based on enzyme immunoprecipitation. In addition, the H2O2 secreted from the cells cultured in different dimensions (suspension of single cells and three-dimensional cell spheroids) treated with identical drugs is measured and compared. The spheroid samples can be prepared with ample amount using a designed microfluidic device with precise control of size. The results show that the H2O2 secretion from the cells are great affected by their culture formats.
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Affiliation(s)
- Yang-Jyun Siao
- Institute of Biophotonics, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Chien-Chung Peng
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Chung Tung
- Institute of Biophotonics, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
- *Correspondence: Yi-Chung Tung, ; Yih-Fan Chen,
| | - Yih-Fan Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
- *Correspondence: Yi-Chung Tung, ; Yih-Fan Chen,
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12
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Hussain K, Liu R, Smith RCG, Müller KTJ, Ghorbani M, Macari S, Cleary KLS, Oldham RJ, Foxall RB, James S, Booth SG, Murray T, Dahal LN, Hargreaves CE, Kemp RS, Longley J, Douglas J, Markham H, Chee SJ, Stopforth RJ, Roghanian A, Carter MJ, Ottensmeier CH, Frendéus B, Cutress RI, French RR, Glennie MJ, Strefford JC, Thirdborough SM, Beers SA, Cragg MS. HIF activation enhances FcγRIIb expression on mononuclear phagocytes impeding tumor targeting antibody immunotherapy. J Exp Clin Cancer Res 2022; 41:131. [PMID: 35392965 PMCID: PMC8988350 DOI: 10.1186/s13046-022-02294-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 02/20/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Hypoxia is a hallmark of the tumor microenvironment (TME) and in addition to altering metabolism in cancer cells, it transforms tumor-associated stromal cells. Within the tumor stromal cell compartment, tumor-associated macrophages (TAMs) provide potent pro-tumoral support. However, TAMs can also be harnessed to destroy tumor cells by monoclonal antibody (mAb) immunotherapy, through antibody dependent cellular phagocytosis (ADCP). This is mediated via antibody-binding activating Fc gamma receptors (FcγR) and impaired by the single inhibitory FcγR, FcγRIIb. METHODS We applied a multi-OMIC approach coupled with in vitro functional assays and murine tumor models to assess the effects of hypoxia inducible factor (HIF) activation on mAb mediated depletion of human and murine cancer cells. For mechanistic assessments, siRNA-mediated gene silencing, Western blotting and chromatin immune precipitation were utilized to assess the impact of identified regulators on FCGR2B gene transcription. RESULTS We report that TAMs are FcγRIIbbright relative to healthy tissue counterparts and under hypoxic conditions, mononuclear phagocytes markedly upregulate FcγRIIb. This enhanced FcγRIIb expression is transcriptionally driven through HIFs and Activator protein 1 (AP-1). Importantly, this phenotype reduces the ability of macrophages to eliminate anti-CD20 monoclonal antibody (mAb) opsonized human chronic lymphocytic leukemia cells in vitro and EL4 lymphoma cells in vivo in human FcγRIIb+/+ transgenic mice. Furthermore, post-HIF activation, mAb mediated blockade of FcγRIIb can partially restore phagocytic function in human monocytes. CONCLUSION Our findings provide a detailed molecular and cellular basis for hypoxia driven resistance to antitumor mAb immunotherapy, unveiling a hitherto unexplored aspect of the TME. These findings provide a mechanistic rationale for the modulation of FcγRIIb expression or its blockade as a promising strategy to enhance approved and novel mAb immunotherapies.
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Affiliation(s)
- Khiyam Hussain
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Rena Liu
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Rosanna C G Smith
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Kri T J Müller
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Mohammadmersad Ghorbani
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
- Cancer Genomics Group, Southampton Experimental Cancer Medicine Centre, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Sofia Macari
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Kirstie L S Cleary
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Robert J Oldham
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Russell B Foxall
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Sonya James
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Steven G Booth
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Tom Murray
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Lekh N Dahal
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Chantal E Hargreaves
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
- Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Robert S Kemp
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Jemma Longley
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - James Douglas
- University Hospital Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, Hampshire, UK
| | - Hannah Markham
- University Hospital Southampton, Southampton General Hospital, Tremona Road, Southampton, SO16 6YD, Hampshire, UK
| | - Serena J Chee
- CRUK Southampton Centre, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Richard J Stopforth
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Ali Roghanian
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Matthew J Carter
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Christian H Ottensmeier
- CRUK Southampton Centre, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Bjorn Frendéus
- Preclinical Research, BioInvent International AB, Sölvegatan 41, 22370, Lund, Sweden
| | - Ramsey I Cutress
- CRUK Southampton Centre, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Ruth R French
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Martin J Glennie
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Jonathan C Strefford
- Cancer Genomics Group, Southampton Experimental Cancer Medicine Centre, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Stephen M Thirdborough
- CRUK Southampton Centre, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK
| | - Stephen A Beers
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK.
| | - Mark S Cragg
- Antibody and Vaccine Group, Centre for Cancer Immunology, School of Cancer Sciences, Faculty of Medicine, University of Southampton, Tremona Road, Southampton, SO16 6YD, UK.
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13
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The Effect of Oxygen and Micronutrient Composition of Cell Growth Media on Cancer Cell Bioenergetics and Mitochondrial Networks. Biomolecules 2021; 11:biom11081177. [PMID: 34439843 PMCID: PMC8391631 DOI: 10.3390/biom11081177] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/20/2021] [Accepted: 08/05/2021] [Indexed: 01/14/2023] Open
Abstract
Cancer cell culture is routinely performed under superphysiologic O2 levels and in media such as Dulbecco's Modified Eagle Medium (DMEM) with nutrient composition dissimilar to mammalian extracellular fluid. Recently developed cell culture media (e.g., Plasmax, Human Plasma-Like Medium (HPLM)), which are modeled on the metabolite composition of human blood plasma, have been shown to shift key cellular activities in several cancer cell lines. Similar effects have been reported with respect to O2 levels in cell culture. Given these observations, we investigated how media composition and O2 levels affect cellular energy metabolism and mitochondria network structure in MCF7, SaOS2, LNCaP, and Huh7 cells. Cells were cultured in physiologic (5%) or standard (18%) O2 levels, and in physiologic (Plasmax) or standard cell culture media (DMEM). We show that both O2 levels and media composition significantly affect mitochondrial abundance and network structure, concomitantly with changes in cellular bioenergetics. Extracellular acidification rate (ECAR), a proxy for glycolytic activity, was generally higher in cells cultured in DMEM while oxygen consumption rates (OCR) were lower. This effect of media on energy metabolism is an important consideration for the study of cancer drugs that target aspects of energy metabolism, including lactate dehydrogenase activity.
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14
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Abbas M, Moradi F, Hu W, Regudo KL, Osborne M, Pettipas J, Atallah DS, Hachem R, Ott-Peron N, Stuart JA. Vertebrate cell culture as an experimental approach – limitations and solutions. Comp Biochem Physiol B Biochem Mol Biol 2021; 254:110570. [DOI: 10.1016/j.cbpb.2021.110570] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/13/2021] [Accepted: 01/21/2021] [Indexed: 02/06/2023]
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15
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Tse HM, Gardner G, Dominguez-Bendala J, Fraker CA. The Importance of Proper Oxygenation in 3D Culture. Front Bioeng Biotechnol 2021; 9:634403. [PMID: 33859979 PMCID: PMC8042214 DOI: 10.3389/fbioe.2021.634403] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 03/09/2021] [Indexed: 12/15/2022] Open
Abstract
Cell culture typically employs inexpensive, disposable plasticware, and standard humidified CO2/room air incubators (5% CO2, ∼20% oxygen). These methods have historically proven adequate for the maintenance of viability, function, and proliferation of many cell types, but with broad variation in culture practices. With technological advances it is becoming increasingly clear that cell culture is not a “one size fits all” procedure. Recently, there is a shift toward comprehension of the individual physiological niches of cultured cells. As scale-up production of single cell and 3D aggregates for therapeutic applications has expanded, researchers have focused on understanding the role of many environmental metabolites/forces on cell function and viability. Oxygen, due to its role in cell processes and the requirement for adequate supply to maintain critical energy generation, is one such metabolite gaining increased focus. With the advent of improved sensing technologies and computational predictive modeling, it is becoming evident that parameters such as cell seeding density, culture media height, cellular oxygen consumption rate, and aggregate dimensions should be considered for experimental reproducibility. In this review, we will examine the role of oxygen in 3D cell culture with particular emphasis on primary islets of Langerhans and stem cell-derived insulin-producing SC-β cells, both known for their high metabolic demands. We will implement finite element modeling (FEM) to simulate historical and current culture methods in referenced manuscripts and innovations focusing on oxygen distribution. Our group and others have shown that oxygen plays a key role in proliferation, differentiation, and function of these 3D aggregates. Their culture in plastic consistently results in core regions of hypoxia/anoxia exacerbated by increased media height, aggregate dimensions, and oxygen consumption rates. Static gas permeable systems ameliorate this problem. The use of rotational culture and other dynamic culture systems also have advantages in terms of oxygen supply but come with the caveat that these endocrine aggregates are also exquisitely sensitive to mechanical perturbation. As recent work demonstrates, there is a strong rationale for the use of alternate in vitro systems to maintain physio-normal environments for cell growth and function for better phenotypic approximation of in vivo counterparts.
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Affiliation(s)
- Hubert M Tse
- Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Graeme Gardner
- Department of Surgery, Diabetes Research Institute, Leonard M. Miller School of Medicine, University of Miami, Coral Gables, FL, United States
| | - Juan Dominguez-Bendala
- Department of Surgery, Diabetes Research Institute, Leonard M. Miller School of Medicine, University of Miami, Coral Gables, FL, United States.,Department of Cell Biology and Anatomy, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Christopher A Fraker
- Department of Surgery, Diabetes Research Institute, Leonard M. Miller School of Medicine, University of Miami, Coral Gables, FL, United States
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16
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Fojtík P, Beckerová D, Holomková K, Šenfluk M, Rotrekl V. Both Hypoxia-Inducible Factor 1 and MAPK Signaling Pathway Attenuate PI3K/AKT via Suppression of Reactive Oxygen Species in Human Pluripotent Stem Cells. Front Cell Dev Biol 2021; 8:607444. [PMID: 33553145 PMCID: PMC7859355 DOI: 10.3389/fcell.2020.607444] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/15/2020] [Indexed: 12/15/2022] Open
Abstract
Mild hypoxia (5% O2) as well as FGFR1-induced activation of phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B (PI3K/AKT) and MAPK signaling pathways markedly support pluripotency in human pluripotent stem cells (hPSCs). This study demonstrates that the pluripotency-promoting PI3K/AKT signaling pathway is surprisingly attenuated in mild hypoxia compared to the 21% O2 environment. Hypoxia is known to be associated with lower levels of reactive oxygen species (ROS), which are recognized as intracellular second messengers capable of upregulating the PI3K/AKT signaling pathway. Our data denote that ROS downregulation results in pluripotency upregulation and PI3K/AKT attenuation in a hypoxia-inducible factor 1 (HIF-1)-dependent manner in hPSCs. Using specific MAPK inhibitors, we show that the MAPK pathway also downregulates ROS and therefore attenuates the PI3K/AKT signaling—this represents a novel interaction between these signaling pathways. This inhibition of ROS initiated by MEK1/2–ERK1/2 may serve as a negative feedback loop from the MAPK pathway toward FGFR1 and PI3K/AKT activation. We further describe the molecular mechanism resulting in PI3K/AKT upregulation in hPSCs—ROS inhibit the PI3K's primary antagonist PTEN and upregulate FGFR1 phosphorylation. These novel regulatory circuits utilizing ROS as second messengers may contribute to the development of enhanced cultivation and differentiation protocols for hPSCs. Since the PI3K/AKT pathway often undergoes an oncogenic transformation, our data could also provide new insights into the regulation of cancer stem cell signaling.
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Affiliation(s)
- Petr Fojtík
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Brno, Czechia
| | - Deborah Beckerová
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Brno, Czechia
| | - Katerina Holomková
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Martin Šenfluk
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Brno, Czechia
| | - Vladimir Rotrekl
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czechia.,International Clinical Research Center (ICRC), St. Anne's University Hospital, Brno, Czechia
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17
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Hass DT, Barnstable CJ. Uncoupling proteins in the mitochondrial defense against oxidative stress. Prog Retin Eye Res 2021; 83:100941. [PMID: 33422637 DOI: 10.1016/j.preteyeres.2021.100941] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/28/2020] [Accepted: 01/03/2021] [Indexed: 02/06/2023]
Abstract
Oxidative stress is a major component of most major retinal diseases. Many extrinsic anti-oxidative strategies have been insufficient at counteracting one of the predominant intrinsic sources of reactive oxygen species (ROS), mitochondria. The proton gradient across the inner mitochondrial membrane is a key driving force for mitochondrial ROS production, and this gradient can be modulated by members of the mitochondrial uncoupling protein (UCP) family. Of the UCPs, UCP2 shows a widespread distribution and has been shown to uncouple oxidative phosphorylation, with concomitant decreases in ROS production. Genetic studies using transgenic and knockout mice have documented the ability of increased UCP2 activity to provide neuroprotection in models of a number of diseases, including retinal diseases, indicating that it is a strong candidate for a therapeutic target. Molecular studies have identified the structural mechanism of action of UCP2 and have detailed the ways in which its expression and activity can be controlled at the transcriptional, translational and posttranslational levels. These studies suggest a number of ways in control of UCP2 expression and activity can be used therapeutically for both acute and chronic conditions. The development of such therapeutic approaches will greatly increase the tools available to combat a broad range of serious retinal diseases.
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Affiliation(s)
- Daniel T Hass
- Department of Biochemistry, The University of Washington, Seattle, WA, 98109, USA
| | - Colin J Barnstable
- Department of Neural and Behavioral Sciences, The Pennsylvania State University, Hershey, PA, 17033, USA.
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18
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Abstract
Significance: Oxidative stress in moderation positively affects homeostasis through signaling, while in excess it is associated with adverse health outcomes. Both activities are generally attributed to reactive oxygen species (ROS); hydrogen peroxide as the signal, and cysteines on regulatory proteins as the target. However, using antioxidants to affect signaling or benefit health has not consistently translated into expected outcomes, or when it does, the mechanism is often unclear. Recent Advances: Reactive sulfur species (RSS) were integral in the origin of life and throughout much of evolution. Sophisticated metabolic pathways that evolved to regulate RSS were easily "tweaked" to deal with ROS due to the remarkable similarities between the two. However, unlike ROS, RSS are stored, recycled, and chemically more versatile. Despite these observations, the relevance and regulatory functions of RSS in extant organisms are generally underappreciated. Critical Issues: A number of factors bias observations in favor of ROS over RSS. Research conducted in room air is hyperoxic to cells, and promotes ROS production and RSS oxidation. Metabolic rates of rodent models greatly exceed those of humans; does this favor ROS? Analytical methods designed to detect ROS also respond to RSS. Do these disguise the contributions of RSS? Future Directions: Resolving the ROS/RSS issue is vital to understand biology in general and human health in particular. Improvements in experimental design and analytical methods are crucial. Perhaps the most important is an appreciation of all the attributes of RSS and keeping an open mind.
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Affiliation(s)
- Kenneth R Olson
- Department of Physiology, Indiana University School of Medicine-South Bend, South Bend, Indiana, USA
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19
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Hamstra SI, Whitley KC, Baranowski RW, Kurgan N, Braun JL, Messner HN, Fajardo VA. The role of phospholamban and GSK3 in regulating rodent cardiac SERCA function. Am J Physiol Cell Physiol 2020; 319:C694-C699. [PMID: 32755452 DOI: 10.1152/ajpcell.00318.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac contractile function is largely mediated by the regulation of Ca2+ cycling throughout the lifespan. The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump is paramount to cardiac Ca2+ regulation, and it is well established that SERCA dysfunction pathologically contributes to cardiomyopathy and heart failure. Phospholamban (PLN) is a well-known inhibitor of the SERCA pump and its regulation of SERCA2a-the predominant cardiac SERCA isoform-contributes significantly to proper cardiac function. Glycogen synthase kinase 3 (GSK3) is a serine/threonine kinase involved in several metabolic pathways, and we and others have shown that it regulates SERCA function. In this mini-review, we highlight the underlying mechanisms behind GSK3's regulation of SERCA function specifically discussing changes in SERCA2a and PLN expression and its potential protection against oxidative stress. Ultimately, these recent findings that we discuss could have clinical implications in the treatment and prevention of cardiomyopathies and heart failure.
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Affiliation(s)
- Sophie I Hamstra
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Kennedy C Whitley
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Ryan W Baranowski
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Nigel Kurgan
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Jessica L Braun
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Holt N Messner
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Val A Fajardo
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
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Olson KR. Reactive oxygen species or reactive sulfur species: why we should consider the latter. ACTA ACUST UNITED AC 2020; 223:223/4/jeb196352. [PMID: 32102833 DOI: 10.1242/jeb.196352] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The biological effects of oxidants, especially reactive oxygen species (ROS), include signaling functions (oxidative eustress), initiation of measures to reduce elevated ROS (oxidative stress), and a cascade of pathophysiological events that accompany excessive ROS (oxidative distress). Although these effects have long been studied in animal models with perturbed ROS, their actions under physiological conditions are less clear. I propose that some of the apparent uncertainty may be due to confusion of ROS with endogenously generated reactive sulfur species (RSS). ROS and RSS are chemically similar, but RSS are more reactive and versatile, and can be stored and reused. Both ROS and RSS signal via oxidation reactions with protein cysteine sulfur and they produce identical effector responses, but RSS appear to be more effective. RSS in the form of persulfidated cysteines (Cys-S-S) are produced endogenously and co-translationally introduced into proteins, and there is increasing evidence that many cellular proteins are persulfidated. A number of practical factors have contributed to confusion between ROS and RSS, and these are discussed herein. Furthermore, essentially all endogenous antioxidant enzymes appeared shortly after life began, some 3.8 billion years ago, when RSS metabolism dominated evolution. This was long before the rise in ROS, 600 million years ago, and I propose that these same enzymes, with only minor modifications, still effectively metabolize RSS in extant organisms. I am not suggesting that all ROS are RSS; however, I believe that the relative importance of ROS and RSS in biological systems needs further consideration.
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Affiliation(s)
- Kenneth R Olson
- Indiana University School of Medicine-South Bend, Raclin Carmichael Hall, 1234 Notre Dame Avenue, South Bend, IN 46617, USA
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Pavlacky J, Polak J. Technical Feasibility and Physiological Relevance of Hypoxic Cell Culture Models. Front Endocrinol (Lausanne) 2020; 11:57. [PMID: 32153502 PMCID: PMC7046623 DOI: 10.3389/fendo.2020.00057] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 01/29/2020] [Indexed: 12/13/2022] Open
Abstract
Hypoxia is characterized as insufficient oxygen delivery to tissues and cells in the body and is prevalent in many human physiology processes and diseases. Thus, it is an attractive state to experimentally study to understand its inner mechanisms as well as to develop and test therapies against pathological conditions related to hypoxia. Animal models in vivo fail to recapitulate some of the key hallmarks of human physiology, which leads to human cell cultures; however, they are prone to bias, namely when pericellular oxygen concentration (partial pressure) does not respect oxygen dynamics in vivo. A search of the current literature on the topic revealed this was the case for many original studies pertaining to experimental models of hypoxia in vitro. Therefore, in this review, we present evidence mandating for the close control of oxygen levels in cell culture models of hypoxia. First, we discuss the basic physical laws required for understanding the oxygen dynamics in vitro, most notably the limited diffusion through a liquid medium that hampers the oxygenation of cells in conventional cultures. We then summarize up-to-date knowledge of techniques that help standardize the culture environment in a replicable fashion by increasing oxygen delivery to the cells and measuring pericellular levels. We also discuss how these tools may be applied to model both constant and intermittent hypoxia in a physiologically relevant manner, considering known values of partial pressure of tissue normoxia and hypoxia in vivo, compared to conventional cultures incubated at rigid oxygen pressure. Attention is given to the potential influence of three-dimensional tissue cultures and hypercapnia management on these models. Finally, we discuss the implications of these concepts for cell cultures, which try to emulate tissue normoxia, and conclude that the maintenance of precise oxygen levels is important in any cell culture setting.
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Affiliation(s)
- Jiri Pavlacky
- Department of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czechia
- Rare Diseases Research Unit, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Polak
- Department of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czechia
- *Correspondence: Jan Polak
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Kurgan N, Whitley KC, Maddalena LA, Moradi F, Stoikos J, Hamstra SI, Rubie EA, Kumar M, Roy BD, Woodgett JR, Stuart JA, Fajardo VA. A Low-Therapeutic Dose of Lithium Inhibits GSK3 and Enhances Myoblast Fusion in C2C12 Cells. Cells 2019; 8:cells8111340. [PMID: 31671858 PMCID: PMC6912290 DOI: 10.3390/cells8111340] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/23/2019] [Accepted: 10/26/2019] [Indexed: 12/14/2022] Open
Abstract
Glycogen synthase kinase 3 (GSK3) slows myogenic differentiation and myoblast fusion partly by inhibiting the Wnt/β-catenin signaling pathway. Lithium, a common medication for bipolar disorder, inhibits GSK3 via Mg+ competition and increased Ser21 (GSK3α) or Ser9 (GSK3β) phosphorylation, leading to enhanced myoblast fusion and myogenic differentiation. However, previous studies demonstrating the effect of lithium on GSK3 have used concentrations up to 10 mM, which greatly exceeds concentrations measured in the serum of patients being treated for bipolar disorder (0.5–1.2 mM). Here, we determined whether a low-therapeutic (0.5 mM) dose of lithium could promote myoblast fusion and myogenic differentiation in C2C12 cells. C2C12 myotubes differentiated for three days in media containing 0.5 mM lithium chloride (LiCl) had significantly higher GSK3β (ser9) and GSK3α (ser21) phosphorylation compared with control myotubes differentiated in the same media without LiCl (+2–2.5 fold, p < 0.05), a result associated with an increase in total β-catenin. To further demonstrate that 0.5 mM LiCl inhibited GSK3 activity, we also developed a novel GSK3-specific activity assay. Using this enzyme-linked spectrophotometric assay, we showed that 0.5 mM LiCl-treated myotubes had significantly reduced GSK3 activity (−86%, p < 0.001). Correspondingly, 0.5 mM LiCl treated myotubes had a higher myoblast fusion index compared with control (p < 0.001) and significantly higher levels of markers of myogenesis (myogenin, +3-fold, p < 0.001) and myogenic differentiation (myosin heavy chain, +10-fold, p < 0.001). These results indicate that a low-therapeutic dose of LiCl is sufficient to promote myoblast fusion and myogenic differentiation in muscle cells, which has implications for the treatment of several myopathic conditions.
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Affiliation(s)
- Nigel Kurgan
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Kennedy C. Whitley
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Lucas A. Maddalena
- Department of Biological Sciences, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (L.A.M.); (F.M.); (J.A.S.)
| | - Fereshteh Moradi
- Department of Biological Sciences, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (L.A.M.); (F.M.); (J.A.S.)
| | - Joshua Stoikos
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
| | - Sophie I. Hamstra
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Elizabeth A. Rubie
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON M5G 1X5, Canada; (E.A.R.); (M.K.); (J.R.W.)
| | - Megha Kumar
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON M5G 1X5, Canada; (E.A.R.); (M.K.); (J.R.W.)
| | - Brian D. Roy
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - James R. Woodgett
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON M5G 1X5, Canada; (E.A.R.); (M.K.); (J.R.W.)
| | - Jeffrey A. Stuart
- Department of Biological Sciences, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (L.A.M.); (F.M.); (J.A.S.)
| | - Val A. Fajardo
- Department of Kinesiology, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada; (N.K.); (K.C.W.); (J.S.); (S.I.H.); (B.D.R.)
- Centre for Bone and Muscle Health, Brock University 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
- Correspondence:
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Olson KR. Hydrogen sulfide, reactive sulfur species and coping with reactive oxygen species. Free Radic Biol Med 2019; 140:74-83. [PMID: 30703482 DOI: 10.1016/j.freeradbiomed.2019.01.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/19/2018] [Accepted: 01/18/2019] [Indexed: 12/31/2022]
Abstract
Life began in a ferruginous (anoxic and Fe2+ dominated) world around 3.8 billion years ago (bya). Hydrogen sulfide (H2S) and other sulfur molecules from hydrothermal vents and other fissures provided many key necessities for life's origin including catalytic platforms (primordial enzymes) that also served as primitive boundaries (cell walls), substrates for organic synthesis and a continuous source of energy in the form of reducing equivalents. Anoxigenic photosynthesis oxidizing H2S followed within a few hundred million years and laid the metabolic groundwork for oxidative photosynthesis some half-billion years later that slightly and episodically increased atmospheric oxygen around 2.3 bya. This oxidized terrestrial sulfur to sulfate which was washed to the sea where it was reduced creating vast euxinic (anoxic and sulfidic) areas. It was in this environment that eukaryotic cells appeared around 1.5 bya and where they evolved for nearly 1 billion additional years. Oxidative photosynthesis finally oxidized the oceans and around 0.6 bya oxygen levels in the atmosphere and oceans began to rise toward present day levels. This is purported to have been a life-threatening event due to the prevalence of reactive oxygen species (ROS) and thus necessitated the elaboration of chemical and enzymatic antioxidant mechanisms. However, these antioxidants initially appeared around the time of anoxigenic photosynthesis suggesting a commitment to metabolism of reactive sulfur species (RSS). This review examines these events and suggests that many of the biological attributes assigned to ROS may, in fact, be due to RSS. This is underscored by observations that ROS and RSS are chemically similar, often indistinguishable by analytical methods and the fact that the bulk of biochemical and physiological experiments are performed in unphysiologically oxic environments where ROS are artifactually favored over RSS.
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Affiliation(s)
- Kenneth R Olson
- Indiana University School of Medicine-South Bend, Raclin Carmichael Hall, 1234 Notre Dame Ave, South Bend, IN 46617, USA.
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Bagshaw ORM, De Lange M, Renda S, Valente AJF, Stuart JA. Hypoxio: a simple solution to preventing pericellular hypoxia in cell monolayers growing at physiological oxygen levels. Cytotechnology 2019; 71:873-879. [PMID: 31250233 PMCID: PMC6663961 DOI: 10.1007/s10616-019-00326-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 06/22/2019] [Indexed: 12/15/2022] Open
Abstract
Culturing cells as adherent monolayers is a common approach in cell biology. For cell culture experiments to yield reliable results it is important to replicate in vivo conditions as faithfully as possible. Increasingly, researchers appreciate the importance of oxygen in cell physiology and the corresponding need to maintain physiologically relevant oxygen levels during experiments. However, although oxygen levels are sometimes monitored over the course of an experiment, this is virtually always in the incubator gas phase and not in the media bathing cells. When incubator oxygen levels are set to a physiologically appropriate level, typically 2-6%, the pericellular oxygen levels experienced by cells may be substantially lower, particularly under conditions where cells are respiring rapidly. We have developed a simple approach to prevent this problem. 'Hypoxio' is a software application that uses real time measurements of pericellular oxygen to coordinate media mixing via a tilt table. Hypoxio allows the user to set a threshold below which it initiates a mixing cycle of user-adjustable duration to abolish standing gradients associated with pericellular hypoxia. Here we describe Hypoxio, demonstrate its efficacy, and direct the reader to our GitHub site for downloadabale software and a description of hardware.
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Affiliation(s)
- Olivia R M Bagshaw
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Michael De Lange
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Stephen Renda
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Andrew J F Valente
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada
| | - Jeffrey A Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada.
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Prolo C, Rios N, Piacenza L, Álvarez MN, Radi R. Fluorescence and chemiluminescence approaches for peroxynitrite detection. Free Radic Biol Med 2018; 128:59-68. [PMID: 29454880 DOI: 10.1016/j.freeradbiomed.2018.02.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/07/2018] [Accepted: 02/12/2018] [Indexed: 12/23/2022]
Abstract
In the last two decades, there has been a significant advance in understanding the biochemistry of peroxynitrite, an endogenously-produced oxidant and nucleophile. Its relevance as a mediator in several pathologic states and the aging process together with its transient character and low steady-state concentration, motivated the development of a variety of techniques for its unambiguous detection and estimation. Among these, fluorescence and chemiluminescence approaches have represented important tools with enhanced sensitivity but usual limited specificity. In this review, we analyze selected examples of molecular probes that permit the detection of peroxynitrite by fluorescence and chemiluminescence, disclosing their mechanism of reaction with either peroxynitrite or peroxynitrite-derived radicals. Indeed, probes have been divided into 1) redox probes that yield products by a free radical mechanism, and 2) electrophilic probes that evolve to products secondary to the nucleophilic attack by peroxynitrite. Overall, boronate-based compounds are emerging as preferred probes for the sensitive and specific detection and quantitation. Moreover, novel strategies involving genetically-modified fluorescent proteins with the incorporation of unnatural amino acids have been recently described as peroxynitrite sensors. This review analyzes the most commonly used fluorescence and chemiluminescence approaches for peroxynitrite detection and provides some guidelines for appropriate experimental design and data interpretation, including how to estimate peroxynitrite formation rates in cells.
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Affiliation(s)
- Carolina Prolo
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Natalia Rios
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Lucia Piacenza
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - María Noel Álvarez
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Rafael Radi
- Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay; Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
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Fonseca J, Moradi F, Valente AJF, Stuart JA. Oxygen and Glucose Levels in Cell Culture Media Determine Resveratrol's Effects on Growth, Hydrogen Peroxide Production, and Mitochondrial Dynamics. Antioxidants (Basel) 2018; 7:E157. [PMID: 30400646 PMCID: PMC6262276 DOI: 10.3390/antiox7110157] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/23/2018] [Accepted: 11/02/2018] [Indexed: 11/24/2022] Open
Abstract
Resveratrol is a plant-derived polyphenol that has been widely studied for its putative health promoting effects. Many of those studies have been conducted in cell culture, in supra-physiological levels of oxygen and glucose. Resveratrol interacts with reactive oxygen species (ROS) as an antioxidant or pro-oxidant. Resveratrol affects the expression and activities of ROS-producing enzymes and organelles. It is therefore important to consider how cell culture conditions might determine the effects of resveratrol on cultured cells. We determined the effects of resveratrol on cell growth, hydrogen peroxide production, and mitochondrial network characteristics in C2C12 mouse myoblasts and PC3 human prostate cancer cells under conditions of physiological (5%) and supra-physiological (18%) oxygen, and normo- (5 mM) and hyper-glycemia (25 mM). Interestingly, most effects of resveratrol on the parameters measured here were dependent upon prevailing oxygen and glucose levels during the experiment. Many of the effects of resveratrol on cell growth, hydrogen peroxide production, and mitochondrial network characteristics that were seen in 25 mM glucose and/or 18% oxygen were absent under the physiologically relevant conditions of 5 mM glucose with 5% oxygen. These findings emphasize the importance of using physiologically meaningful starting conditions for cell-culture experiments with resveratrol and indeed any manipulation affecting ROS metabolism and mitochondria.
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Affiliation(s)
- Joao Fonseca
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada.
| | - Fereshteh Moradi
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada.
| | - Andrew J F Valente
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada.
| | - Jeffrey A Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada.
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How Supraphysiological Oxygen Levels in Standard Cell Culture Affect Oxygen-Consuming Reactions. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:8238459. [PMID: 30363917 PMCID: PMC6186316 DOI: 10.1155/2018/8238459] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/01/2018] [Indexed: 12/31/2022]
Abstract
Most mammalian tissue cells experience oxygen partial pressures in vivo equivalent to 1–6% O2 (i.e., physioxia). In standard cell culture, however, headspace O2 levels are usually not actively regulated and under these conditions are ~18%. This drives hyperoxia in cell culture media that can affect a wide variety of cellular activities and may compromise the ability of in vitro models to reproduce in vivo biology. Here, we review and discuss some specific O2-consuming organelles and enzymes, including mitochondria, NADPH oxidases, the transplasma membrane redox system, nitric oxide synthases, xanthine oxidase, and monoamine oxidase with respect to their sensitivities to O2 levels. Many of these produce reactive oxygen and/or nitrogen species (ROS/RNS) as either primary end products or byproducts and are acutely sensitive to O2 levels in the range from 1% to 18%. Interestingly, many of them are also transcriptional targets of hypoxia-inducible factors (HIFs) and chronic cell growth at physioxia versus 18% O2 may alter their expression. Aquaporins, which facilitate hydrogen peroxide diffusion into and out of cells, are also regulated by HIFs, indicating that O2 levels may affect intercellular communication via hydrogen peroxide. The O2 sensitivities of these important activities emphasize the importance of maintaining physioxia in culture.
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